I remember very clearly what would nowadays be called my spiritual awakening, the moment when faith became something personal to me. Until that day, I had been an extremely lucky child. I had a loving family and a comfortable life, and my father was a successful lawyer.

When I was 10, my father, just 40, suffered a severe stroke and was rushed to the hospital. The doctors were uncertain if he would survive. My mother, trying to keep a sense of normality for her children, sent us to school that morning.

To provide comfort to a frightened and bewildered boy, the head teacher, who was ordained, suggested that he and I kneel and pray for my father's recovery. I knew this was not as straightforward as he thought, and I plucked up the courage to whisper, "I'm afraid my father doesn't believe in God."

My teacher's reply was to make a lasting impression on me. "That doesn't matter," the man said. "God believes in him. He loves him without demanding or needing love in return."

My father ended up making a good recovery after a long rehabilitation. Nearly 50 years later, he remains an atheist. And while I did not become a fully committed and practicing Christian overnight, that conversation with my teacher started the process in which I came to recognize that there is a purpose to our existence beyond ourselves.

I was confirmed while I was at college, and faith has been a constant in my life. Yet even for nonbelievers, faith cannot be ignored. Today, religious beliefs -- whether Christian, Jewish, Muslim, Hindu, or other creeds -- are at the core of the lives of two-thirds of the world's population, giving them sense and direction. And it is not only a matter of numbers -- faith matters because it inspires people to act and raise their sights beyond themselves.

Sadly, religion can be distorted into violent extremism. Having spiritual beliefs has never rendered a person incapable of doing wrong or evil. But far more often, faith can be a force for good. I have witnessed its positive impact wherever I've gone in the world. I've seen it at major disasters in the incredible humanitarian efforts of the Red Cross, Islamic Relief, or World Jewish Relief, all organizations inspired by belief. I've also seen it in the central role of synagogues, churches, temples, and mosques in helping the poor, vulnerable, and disadvantaged in every country. In every case, men and women of faith who are trying to put the idea of unconditional love into practice are leading these efforts.

We should not allow those who use religion as a divisive force to succeed. We can harness its power and common values to bring us together. This is more important than ever in an age when the Internet, mass communication, and travel are shrinking the world.

None of this means giving up our own beliefs -- I always say that no matter the company, I remain a Christian. But it does require focusing on the vast areas we share and not on the much smaller areas that separate us. Two years ago, I launched the Tony Blair Faith Foundation. Among our projects, we've connected students from different continents and religions to help them learn from one another. We've united faith communities to fight against malaria, a disease that kills one million people a year. And we recently held a competition in which young people around the world created short films that showed what their religious beliefs mean to them.

That idea of unconditional love, which made such an impression on a frightened young boy so long ago, is at the core of all our great faiths. We need to get back to this guiding light. By understanding one another, respecting one another, and acting with one another, we can show why humanity is made not poorer by faith but immeasurably richer.

Tony Blair, who served as Britain's prime minister from 1997 to 2007, is the author of the new memoir "A Journey: My Political Life." To read more about his work, go to tonyblairfaithfoundation.org.